Pump



Feb. 5, 1935. E. o. P. THEGE PUMP Filed Jan. 9, 1955 PA WM5@ PatentedFeb. 5, 1935 UNITED STATES PATENT CFFICE PUBIP Application January 9,1933, Serial No. 650,942 In Sweden July 11, 1932 13 Claims.

The present invention relates to pumps and has particular reference tofuel pumps for supplying liquid fuel to internal combustion engines.

In several forms of pumps as heretofore constructed, the quantity offuel delivered by the pumps is controlled by adjustment of the positionof the pump plunger or equivalent pumping element, but due to theunbalanced pressure on such member of the liquid being pumped theadjustment thereof is accomplished only by the application of suflicientforce to overcome the existing unbalanced uid pressure. In the case offuel pumps for injection engines such pressure is so high thatadjustment of this kind of pump is difficult if not impossible with, forexample, a centrifugal speed governor of practical size.

It is a general object of the present invention to improve upon priorpump construction of this general kind. This is accomplished byproviding a pump in which what may be termed the pumping member of thepump is divided to provide a part adjustable to determine the quantityof fuel delivered by the pump, which part is balanced or substantiallybalanced with respect to liquid pressure, and a second part whichsustains the liquid pressure load incident to the pumping operation.

For a better understanding of the invention and the manner in which theabove mentioned and other and more detailed objects of the invention areattained, reference may be had to the ensuing description of suitableforms of apparatus for carrying the invention into eect.

In the accompanying drawing forming a part of this specification- Fig. 1shows in longitudinal section and in more or less diagrammatic form apump embodying the invention; and

Fig. 2 is a view in longitudinal section of another pump embodying theinvention.

The driving shaft 1 of the pump, Fig. 1, is provided with a cam 2, whichacts upon a roller 3 journaled in a hollow plunger or tappet part 4,which is slidably but not turnably mounted in the pump casing and isforced downwardly toward the cam by a spring 5. The part 4 is providedwith inner screw-threads 6, which engage outer screw-threads 7 providedon a plunger 8, which is reciprocable in the pump casing. The part 4 isprevented from rotating by any suitable means for instance the usualgroove and tongue device. A toothed wheel 9 is turnably but notslideably mounted in the pump casing and may be rotated manually or by agovernor by means of any suitable motion transmitting de- (Cl. 10S-Al)vice. Two arms 10 extend from the toothed wheel 9 downwardly and betweenlateral projections 11 on the plunger 8, so that the plunger is causedto rotate with the toothed wheel 9 as the latter is rotated, but may bemoved axially relative to the same.

12 is the pump delivery chamber, in which the top end of the plunger 8operates. With the said chamber a channel 13 communicates, provided witha fuel admission valve 14 and a delivery valve 15 for the fuel fed bythe pump, for example, to the combustion chamber of the an engine. 16 isan overflow valve, which is acted upon by a spring 17 and through achannel 18 returns to the fuel supplying channel 19 fuel, superuous forthe working stroke of the engine piston. A pin 1tl extends from the saidvalve downwardly into the pump chamber 12 and may be acted upon by theplunger 8 in the manner stated below. A channel 20 extends through theplunger 8 and connects the chamber 12 with a chamber 21 provided in thelower part of the plunger. Chamber 21 may be termed a balancing chambersituated between the parts 4 and 8 and in the embodiment illustratedthis chamber is closed by an auxiliary member in the form`of a plunger22 slidably mounted in and closely fitting the wall of the chamber, andheld by spring 23 against the bottom of the threaded recess in part 4.

The tappet part 4 and plunger part 8 may be said to constitute a dividedor compound pumping member, the latter part being carried by andderiving motion through the former and being adjustable with respectthereto.

During the downward stroke of the pumping member of the fuel pumpdescribed above fuel is sucked into the chamber 12 through channel 19and valve 14 and during the upward stroke of this member, fuel is forcedthrough the valve 15 and into the combustion chamber of the engine.Owing to the fact that chamber l2 communicates with chamber 21, thepressure in chamber 12 is transmitted to chamber 21 and to the auxiliarymember 22, which consequently will be subjected to this pressure duringthe working stroke of the pumping member while the plunger 8 issubjected to practically no unbalanced pressure. If the diameter of themember 22 is equal to the diameter of the top'part of the plunger 8, themember 22 will transmit to part 4, which will in turn transmit to thecam 2, the whole pressure exerted by the fuel while it is being forcedout from the pump chamber 12. Consequently, the plunger 3 is whollyrelieved of the pressure exerted by the fuel and for that reason it mayeasily be adjusted by the governor of the engine.

During its upward stroke the plunger 8 enters into contact with theoverow valve pin 16X at a moment adapted to the load of the `engine andopens valve 16, so that fuel superfluous for the driving of the engineis discharged through the channel 18 to the fuel supplying channel 19.The moment at which the valve 16 is opened is determined in such manner,that the plunger 8 is turned by means of the toothed wheel 9 to a higheror lower position in the part 4, and consequently brings the top end ofplunger 8 to a position nearer to or farther from the overflow valve 16,which results in that the valve is opened at an earlier or later momentrespectively and that a smaller or greater quantity of fuel respectivelyis fed into the combustion chamber of the engine.

In the fuel pump shown in Fig. 2 the plunger part of the pumping memberalso serves as a controlling slide valve by discharging from the pumpchamber at the end of its upward stroke, excess fuel which isunnecessary for the working stroke of the engine piston. The pump isprovided in a casing A. Plunger 24 is slideable in a lining 25 and isprovided at its lower end with outer screwthreads 26, engaging innerscrew-threads 27 of a plunger or tappet part 28. Part 28 is guided bythe lining 29 and is prevented from turning for instance by the knowngroove and tongue connection. Part 28 is forced downwardly by a spring30. The driving shaft 31 of the pump is provided with a cam 32, whichacts upon a sultably shaped roller 34, journaled in an arm 35,`

which is swingable on a pin or shaft 33 and transmits the driving powerto the compound pumping member comprising parts 24 and 28. A worm wheel36 is iournaled on the lining 25 between two abutments, preventing thesame from moving axially. With the said worm wheel 36 meshes a screwspindle`3'1, which is journaled in the 4casing A and may be adjustedmanually or by means of a. governor. Two arms 38 extend downwardly fromthe worm wheel 36 and between lateral projections on the plunger 24, sothat the latter is turned by the worm wheel` 36 when rotated but may bemoved axially relative to the worm wheel 38. Owing to the screw-threadedengagement of the part 24 with the plunger 28, the lplunger 24 may beadjusted to different positions vertically by turning the screw spindle37. 'I'he fuel supplying channel is designated by 40 and communicatesthrough a passage 41 with the space below the spring actuated suctionvalve 43 of the pump. The chamber 44x above the valve 43 commnuicatesthrough channels 44 with the pump chamber 45. 'I'he delivery valve 46 ofthe pump leads to a channel which may be connected to the combustion`chamber of an engine. A channel 47 is provided in the plunger 24 andleads from the pump chamber 45 to a chamber 48 provided in the lower endof the plunger 24. An auxiliary member in the form of a plunger 49 isslideably mounted in the said chamber 48 and flts closely to its wall.Plunger 49 is forced against the bottom of the recess in part 28 by aspring 50. Lateral openings 5l extend from the channel 4'7 and in theouter surface of the plunger 24 a groove 52 is provided, preferablyextending round the plunger. A groove 53 corresponding to the saidgroove 52 is provided in the inner side of the lining 25. Radialopenings 54 and 55 are provided in the top part of the pump, leadingfrom the chamber in which the plunger 24 operates, and to the fuelsupplying channel 40. The distance between the said openings 51 from thelower edge of the groove 53 is equal to the distance between the topedge of the groove 52 and the openings 54.

As the compound pumping member is moved downwardly by the spring 30,fuel is sucked from the supply channel 40 through passage 41, valve 43.channels 44 and into the pump chamber 45. As the compound pumping memberis then moved upwardly by the cam 32, fuel is forced from the chamber 45through the channels 44, past the valve 43, now closed, and into thechamber 44X and further through the valve 46 to the combustion chamberof the engine. As, during the upward motion of the plunger 24, theopenings 51 arrive at the groove 53, the groove 52 at the same timesarrives at the openings 54 and in this manner a passage for fuelsuperfluous for the working stroke of the engine piston and leading fromthe pump chamber 45 is effected viz 47, 51, 53, 52. 54 and 55. 'I'hemoment at which the said passage is opened, is dependent on the positionvertically into which the plunger 24 has been adjusted manually or bythe governor. At a greater load of the engine the compound pumpingmember is shortened, which results in discharging superiiuous fuelthrough the said passage at a later momentthan when this member iselongated at a smaller load of the engine. In the case last mentionedthe plunger 24 operates at a higher position and consequently opens thepassage for the superfluous fuel at an earlier moment. The plunger 24may also be adjusted into such a position vertically that the passage47, 5l, 53, 52, 54 and 55 is opened or will be opened just at thestarting of the upward stroke of the plunger 24, in which case no fuelis fed into the combustion chamber of the engine and the engine willstop.

In the form of apparatus shown'in Fig. 2, as well as in the form shownin Fig. l, the auxiliary member is exposed to the pressure of the fuelin the pump chamber during the working stroke of the pumping member andtransmits this pressure to the tappet part, which in turn transmits thepressure to the actuating cam. The plunger part 24 is, because of thisarrangement, not exposed to unbalanced liquid pressure and acts entirelyas a control member. The governor mentioned above may be of any known orsuitable construction and connected to the screw spindle 37 by a motiontransmitting device of any of the conventional types.

Through the provision of the grooves 52 and 53 a double surface closurebetween the plunger 24 and the lining 25 is effected, which renders theescaping of fuel necessary for the working stroke of the engine pistondiflicult or prevents the same. This is of great importance, because thefuel, while being injected into the combustion chamber of the engine, issubjected to a very great pressure. The surface closure may be stillmore increased through the provision of one or more additional pairs ofgrooves of the shown type.

While in compliance with the patent statutes I have described andillustrated preferred embodiments of the invention by way of example, itwill be apparent to those skilled in the art that the principles of theinvention may be embodied in apparatus of different construction thanthat herein disclosed, and the invention is accordingly to be understoodas embracing all such changes and modifications in the apparatus as mayfall within the scope of the appended claims when construed as broadlyas the state of the prior art warrants.

I claim:

1. In a fuel pump intended especially for feeding fuel into an internalcombustion engine, the combination of a delivery chamber. a dividedmember, a mechanism reciprocating said member, said member comprising apart acted upon by said mechanism and a part adjustable with relation tothe first mentioned part for controlling the quantity of delivered fuel,one end of the adjustable part communicating with the delivery chamber,a counter bore in said adjustable part having a shoulder facing awayfrom the delivery chamber, said counter bore communicating with saiddelivery chamber, and an auxiliary member slidably mounted in thecounter bore, subject to the iiuid pressure therein and resting on thefirst mentioned part of the divided member.

2. A pump as claimed in claim l characterized by the cross sectionalarea of the pressure sustaining auxiliary member being substantiallyequal to the cross sectional area of said one end of the adjustablepart.

3. In a fuel pump intended especially for feeding fuel into internalcombustion engines, the combination of a delivery chamber. a dividedpiston, a mechanism reciprocating said piston, said piston comprising apart acted upon by said mechanism and a part adjustable with relation tothe first mentioned part for controlling the quantity of delivered fuel,one end of the adjustable part communicating with the delivery chamber,a counter bore in said adjustable part having a shoulder facing awayfrom the delivery chamber, said counter bore communicating with saiddelivery chamber, an auxiliary member slidably mounted in the counterbore, subject to the fluid pressure therein and resting on the firstmentioned part of the divided piston, and means for adjusting saidadjustable part.

4. A pump as claimed in claim 3 characterized in that the adjustablepart is arranged like a slide valve for controlling the supply of fuelto the engine.

5. A pump as claimed in claim 3, characterized in that said piston isprovided with a passage communicating with the delivery chamber, adischarge passage in the casing for fuel superfluous for the workingstroke of the engine piston, recesses provided in the surface of theadjustable part between said passages and in the wall of the casingandlcooperating with the recesses of the adjustable part, said recessesand said passages together constituting a flow line for the superfluousfuel when said member is in open position` 6. In reciprocating pumpapparatus, pump actuating mechanism, means providing a pump deliverychamber, a multiple-part pumping member having a first part reciprocatedby said mechanism, a plunger part carried by said first part and workingin said delivery chamber, and means to adjust said plunger part relativeto said first part to determne the quantity of fluid delivered by thepump, said plunger part being subjected at its opposite ends tosubstantially equal total iiuid pressures.

7. In reciprocating pump apparatus, pump actuating mechanism, meansproviding a pump delivery chamber and a multiple-part pumping memberhaving a first part reciprocated by said mechanism and a second partcarried by and deriving motion from said first part and adjustable withrespect to said flrst part to determine the quantity of fluid deliveredby the pump, said pumping member providing a second chamber incommunication with the pump delivery chamber and said second part havingopposed end surfaces exposed respectively to the pressure of uid in saiddelivery chamber and in said second chamber.

8. In reciprocating pump apparatus, pump actuating mechanism, meansproviding a pump delivery chamber, a multiple-part pumping member havinga first part reciprocated by said mechanism and a second part carried byand deriving motion from said first part and adjustable with respect tosaid iirst part to determine the quantity of fluid delivered by thepump, said second part having one end working in said delivery chamber,one of said parts being recessed to provide a second chamber, theopposite end of said second part being exposed to pressure in saidsecond chamber, and a connection providing communication between saidsecond chamber and said delivery chamber.

9. In reciprocating pump apparatus, pump actuating mechanism, meansproviding a pump delivery chamber, a multiple-part pumping member havinga first part reciprocated by said mechanism and a second part carried byand deriving motion from said first part and adjustable with respect tosaid first part to determine the quantity of fluid delivered by thepump, said second part having one end working in said delivery chamberand having a recess in the end of the part opposite said deliverychamber, means moving with said first part and slidably mounted in saidrecess and closing the end of the recess opposite the delivery chamberwhereby to provide a second chamber and a connection placing said secondchamber in communication with said delivery chamber.

10. In reciprocating pump apparatus, pump actuating mechanism, meansproviding a pump delivery chamber and a multiple-part pump member havinga first part reciprccated by said mechanism and a second part carried byand deriving motion from said first part and adjustable with respect tosaid first part to determine the quantity of fluid delivered by thepump, said second part having a first end working in said deliverychamber and having a recess in the end of the part opposite said firstend, means moving with said rst part and slidably mounted in said recessand closing the end of the recess opposite thedelivery chamber wherebyto provide a second chamber, the last mentioned means having an areaexposed to uid pressure substantially equal to the area of said firstend of said second part, and a connection placing said second chamber incommunication with said delivery chamber.

11. In reciprocating pump apparatus, pump actuating mechanism, meansproviding a delivery chamber, a compound pump member comprising aAtappet part reciprocated by said actuating mechanism and having a recesstherein and a pump plunger part having one of its ends threaded in saidrecess to provide for adjustment of the pump plunger part with respectto the tappet part to determine the quantity of fluid delivered by thepump, said plunger part having a first end working in said deliverychamber, the end of said plunger part opposite said first end beingrecessed to provide a second chamber, a connection placing said secondchamber in communication with the delivery chamber, and means for'turnnig one of said parts relative to the other of said parts to effectadjustment of said pump plunger part to change the quantity of ulddelivered by the pump.

12. In reciprocating pump apparatus, pump actuating mechanism, meansproviding a delivery chamber, a compound pump member comprising arotationaily fixed tappet part adapted to be reciprocated by saidmechanism and a rotatably mounted plunger part threaded in said tappetpart, said plunger part having a rst end working in said deliverychamber and means for turning said plunger part to adjust it withrespect to the tappet part to determine the quantity oi' uid deliveredby the pump, the end of said plunger part opposite said first end beingrecessed to provide a second chamber, and a. connection placing saidsecond chamber in communication with said delivery chamber.

13. In reciprocating pump apparatus, pump actuating mechanism, meansproviding a pump delivery chamber, a compound pumping member comprisinga tappet part adapted to be reciprocated by said mechanism and arotatably mounted plunger part threaded in said tappet part, saidplunger part having a rst end workingin said delivery chamber, means forturning said plunger part to adjust it with respect to the tappet partto determine the quantity of iluid delivered by the pump', the end oi'said plunger part opposite said iirst end being recessed to provide asecond chamber, means slidably mounted in said recess and adapted tomove with said tappet part for closing said chamber, and a connectionthrough said plunger part for placing said second chamber incommunication with said delivery chamber.

EDVIN OSSIAN PARCIVAL THEGE.

